Pre-Test

Chapter 12: The Cell Cycle

Pre-Test

1 .

Which of the following is not a function of the mitotic cell cycle in eukaryotes? (Concept 12.1

) [Hint]

asexual reproduction

growth

repair of damaged organs

production of gametes

cell replacement

2 .

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? (Concept 12.1

) [Hint]

46

92

23

23 or 46, depending on the portion of prophase examined

46 or 92, depending on the portion of prophase examined

3 .

The kinetochores _____. (Concept 12.1

) [Hint]

are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers

are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis

are sites at which microtubules attach to chromosomes

of each spindle interdigitate at the cell's equator and then move apart, causing the cell to elongate

attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow

4 .

It is difficult to observe individual chromosomes with a light microscope during interphase because _____. (Concept 12.2

) [Hint]

the DNA has not been replicated yet

they have uncoiled to form long, thin strands

they leave the nucleus and are dispersed to other parts of the cell

sister chromatids do not pair up until division starts

the spindle must move them to the metaphase plate before they become visible

5 .

Which of the following correctly matches a phase of the cell cycle with its description? (Concept 12.2

) [Hint]

M: duplication of DNA

S: immediately precedes cell division

G₂: cell division

G₁: follows cell division

All of the above are correctly matched.

6 .

In some organisms such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this? (Concept 12.2

) [Hint]

a decrease in chromosome number

inability to duplicate DNA

division of the organism into many cells, most lacking nuclei

large cells containing many nuclei

a rapid rate of gamete production

7 .

There are a number of differences between the fission of a bacterium and human cell division. Which of the following is not one of these differences? (Concept 12.2

) [Hint]

A bacterium has only one chromosome.

Duplicated bacterial chromosomes attach to the plasma membrane.

Bacteria are smaller and simpler than human cells.

Bacteria have to duplicate their DNA before dividing.

Human chromosomes are larger and more complex.

8 .

Cytochalasin B is a chemical that disrupts microfilament formation. This chemical would interfere with _____. (Concept 12.2

) [Hint]

DNA replication

formation of the mitotic spindle

cleavage

formation of the cell plate

binary fission

9 .

Cells will usually divide if they receive the proper signal at a checkpoint in the _____ phase of the cell cycle. (Concept 12.3

) [Hint]

M

G₁

S

G₂

cytokinesis

10 .

A benign tumor, but not a malignant tumor, is one in which the cancerous cells _____. (Concept 12.3

) [Hint]

migrate from the initial site of transformation to other organs or tissues

can divide indefinitely if an adequate supply of nutrients is available

remain confined to their original site

have an unusual number of chromosomes

are the result of the transformation of normal cells